Design and evaluation of floating gastro retentive tablets of fixed dose combination of ciprofloxacin and metronidazole

Gastro-retentive drug delivery systems offer the advantage in prolonging the gastric emptying time for drugs having a narrow absorption window in the gastrointestinal tract (GIT) resulting in poor absorption. Ciprofloxacin and metronidazole both have a short half-life resulting in increase in dosage regimen. Metronidazole is a nitro imidazole antibiotic and is ineffective on aerobic bacteria. Ciprofloxacin on the other hand is a broad spectrum fluoroquinolone antibacterial agent, the combination of both, is active against a broad spectrum of obligate anaerobic bacteria. The purpose of this study was to design, optimize and evaluate gastroretentive floating tablet of Metronidazole and Ciprofloxacin hydrochloride combination to increase the residence time in the stomach and thereby giving prolong action of each drug individually. Screening of the various grades of HPMC polymer for optimization of matrix forming polymer, followed by optimization of the ratio of the polymer, and the quantity of the swelling agent guar gum. The micromeritic properties, tablet evaluation properties, floating behavior and drug release studies for ciprofloxacin and metronidazole were conducted as per guidelines and compared to the marketed product dissolution profile. The tablets showed acceptable physicochemical properties. The optimization showed that HPMC E10M and HPMC K100M in the ratio of 1:2 were the best suited polymers for the matrix whereas guar gum at 3.3 % was the ideal concentration for the desired floating and drug release profile. The optimized batch was subjected to stability studies at 40 °C/75% RH for 3 months and depicted a stable formulation.